Washing machine mechanism



May 21, 1963 c. E. KURTZ WASHING MACHINE MECHANISM 2 Sheets-Sheet 1 Filed May 22, 1961 May 21, 1963 c. E. KURTZ 3,090,248

WASHING MACHINE MECHANISM Filed May 22, 1961 2 Sheets-Sheet 2 III II f eet e.

. V I I I 44 a 3,090,248 WASHING MACHLNE MECHANESM Curtis E. Kurtz, Herrin, 111., assignor to Borg-Warner Corporation, a corporation of Illinois Filed May 22-, 1961, Ser. No. 111,728 Claims. (61. 74-368) This invention relates to a transmission and more particularly to a four-speed transmission suitable for use in automatic clothes washing machines.

In the operation of automatic clothes washing machines, a single power source is used for driving the laundry basket during the entire laundering operation and includes a low speed washing cycle and a high speed spin cycle to remove the Water from the laundry. A greater amount of torque is required for driving the laundry basket during the washing cycle inasmuch as the basket is heavily loaded by the combined weight of the laundry and water contained therein. Contrasted with this, a lesser torque and a higher speed is required for driving the basket during the spin cycle so as to remove the water from the basket and the clothes by centrifugal force. As the water is removed during the spin cycle, the loading on the laundry basket is continuously reduced so that the spin speed could be increased to expedite removal of the water without unduly loading the drive unit. It is therefore extremely important to be able to provide a transmission for a given drive unit which would automatically provide the necessary low speed and high torque drive for the laundry basket for Washing the clothes and which could be automatically shifted through progressively higher speeds to provide a water-removing spin cycle wherein the spin speed of the laundry basket would be increased in increments as the water is removed therefrom during the spin cycle.

It is a primary object of this invention to provide a sturdy transmission of relatively simple and economical construction for providing a variable speed drive for driving the clothes basket of a clothes washing machine.

Another object of this invention is to provide a compact variable speed transmission having the input shaft positioned coaxially within the output shaft.

A further object of this invention is to provide a variable speed transmission which can be automatically actuated to provide four speeds forward.

Still another object of this invention is to provide a variable speed transmission which requires only two actuating elements for selectively providing four speeds forward.

Another object of this invention is to provide a variable speed transmission having resilient interconnecting speed control elements in the drive train thereof.

With these and other objects in view, the present invention contemplates, among other things, a variable speed transmission having the drive shaft rotatably mounted in a casing and a driven shaft coaxially rotatably mounted in the drive shaft. A series of gears are mounted coaxially on the drive shaft and are respectively in engagement with a series of gears mounted on an idler shaft which, in turn, is rotatably disposed in the easing. Actuatable and overriding spring clutches are provided adjacent predetermined gears within the casing so that four speeds forward are provided by selectively actuating the individual actuatable spring clutches.

The invention consists of the novel constructions, arrangements and devices to be hereinafter described and claimed for carrying out the above-stated objects and such other objects as will appear from the following description of an embodiment of the invention, illustrated with respect to the accompanying drawings, wherein FIG. 1 is a sectional view of a transmission forming Patented May 21, 1963- a preferred embodiment of the invention, said section taken longitudinally through the shafts of the transmission and showing the interrelation of the elements of the transmission.

FIG. 2 is a sectional view of a transmission illustrating another embodiment of the invention, said section being taken longitudinally through the shafts of the transmission showing the interrelation of the elements of the transmission.

Referring to the drawings, there is illustrated a variable speed transmission which is particularly suitable for use in an automatic clothes washing machine. A preferred embodiment of the variable speed transmission is illustrated in FIG. 1 and is generally designated by the numeral 10. The transmission includes, among other things, a drive shaft 11, a driven shaft 12, and an idler shaft 13. The drive shaft 11 is rotatably mounted on a bearing 14 secured within a casing 15 and is provided with a coaxial passage 17. The driven shaft 12 is rotatably mounted coaXially with the drive shaft 11 on bearings 18 within the passage 17 of the drive shaft 11. The right end (FIG. 1) of the driven shaft 12 is rotatably mounted in the casing 15 at 19, and the left end of the driven shaft 12 extends beyond the drive shaft 11 and is adapted to provide a power output portion 20. The idler shaft 13 is rotatably mounted in the casing 15 at 21 and 22 and is positioned parallel to the drive and driven shafts 11 and 12.

A small drive gear 25 is formed on the drive shaft 11 and is provided with a cylindrical clutch drum surface 26. An intermediate drive gear 27 is rotatably mounted on the drive shaft 12 and is provided with a cylindrical clutch drum surface 28 adjacent the drum surface 26 of the drive gear 25. The intermediate drive gear 27 is also provided with a cylindrical clutch drum surface 29 on the opposite side of the gear 27. A first clutch drum 30 having a drum surface 31 is secured to the driven shaft 12 by a pin 32 and is positioned With the drum surface 31 adjacent the drum surface 29 on the intermediate drive gear 27. A large drive gear 33 is rotatably mounted on the driven shaft 12 and is provided with a cylindrical clutch drum surface 34. A second clutch drum 35, having a drum surface 36, is secured to the driven shaft 12 by a pin 37. The second drum surface 36 is positioned adjacent the clutch drum surface 34 of the large drive gear 33.

A large driven gear 38 is rotatably mounted on the idler shaft 13 and is in mesh with the small drive gear 25. The large driven gear 38 is provided with a cylindrical clutch drum surface 39. An intermediate driven gear 40 is secured to the idler shaft 13 by a pin 41 and is in mesh with the intermediate drive gear 27. The intermediate driven gear 40 is provided with a cylindrical clutch drum surface 42 adjacent the clutch drum surface 39 of the large driven gear 38. A small driven gear 43 is secured to the idler shaft 13 by a pin 44 and is in mesh with the large drive gear 33.

A normally engaged, releasable, helical, spring 45 provides a clutch which is mountted on the adjacent clutch surfaces 26 and 28 of the small and intermediate drive gears 25 and 27 respectively and is in frictional engagement with the clutch surfaces 26 and 28. The spring clutch 45 is wound in a direction so as to be self-energizing as a result of the frictional engagement between the spring 45 and the clutch surfaces 26 and 28, during rotation of the drive gear 25. This causes the spring clutch 45 to normally grip the clutch surfaces 26 and 28 and thereby normally effectuate a resilient drive connection between the small and intermediate drive gears 25 and 27. The spring clutch 45 is provided with a laterally extending end portion 46 which, when held stationary during rotation of the drive gear 25, will cause the spring clutch to release its self-energizing gripping relation wi h the clutch surfaces 26 and 28. A solenoid 47 is secured to the casing and is electrically actuatable to cause a plunger 48 to move into the rotational path of the spring end 46 of the spring 45 to hold the end 45 against rotational movement and thereby elfectuate disengagement of the clutch spring 45 with the surfaces 26 and 28 so as to release the resilient drive between the drive gear and the intermediate drive gear 27.

Similarly, a normally engaged, releasable, helical spring clutch 50 is positioned on the cylindrical clutch drum surfaces 29 and 31 of the intermediate drive gear 27 and the clutch drum 30 respectively and is in frictional engagement with the clutch drum surfaces 29 and 31. The spring clutch 50 is wound in a direction so as to be self-energizing as a result of the frictional engagement between the clutch spring 50 and the clutch surfaces 29 and 31 during rotation of the intermediate gear 27. This causes the spring clutch 50 to normally grip the clutch surfaces 29 and 31 and thereby normally eflFectuate a resilient drive connection between the intermediate drive gear 27 and the driven shaft 12 during rotation of the intermediate drive gear 27.

The spring clutch 59 is provided with a radially extending end portion 51 which when held stationary will cause the disengagement of the spring clutch 50 with the clutch drum surfaces 29 and 31. A solenoid 52 secured to the casing 15 and is electrically actuatable to cause a plunger 53 to move into the rotational path of the spring end 51 of the spring clutch 50 to hold the end 51 against rotational movement and thereby elfectuating disengagement of the clutch spring 50 with the surfaces 29 and 31 so as to release the resilient drive between the intermediate drive gear 27 and the driven shaft 12.

A normally engaged, overriding, helical, spring clutch 55 is positioned on the cylindrical clutch drum surface 34 of the large drive gear 33 and the cylindrical clutch drum surface 36 of the clutch drum 35 on the driven shaft 12. The spring clutch 55 is in frictional contact with the clutch drum surfaces 34 and 36 so as to normally provide a resilient self-energizing connection between the large drive gear 33 and the driven shaft 12. The overriding spring clutch 55 is wound in a direction such that it will be caused to disengage when the speed of the driven shaft 12 exceeds that of the large drive gear 33. The driven shaft 12 is thereby permitted to exceed the speed of the large drive gear 33.

Similarly, a normally engaged, helical, overriding, spring clutch 54 is positioned on the cylindrical clutch drum surfaces 39 and 42 of the large and intermediate driven gears 38'and 40. The overriding spring clutch 54 is wound in a direction such that it is self-energizing so as to normally grip the drum surfaces 39 and 42 and provide a resilient driving connection between the large and intermediate driven gears 38 and 40. The direction of the windings of the overriding spring clutch 54 are such that when the speed of the intermediate driven gear 40 exceeds the speed of the large driven gear 38 the spring clutch 54 will be caused to disengage from the clutch drum surfaces 39 and 42 and thereby allow an overriding relationship between the intermediate and large driven gears 40 and 38.

'In operation, the transmission 10 (FIG. 1) is adapted to provide four speeds forward including a low speed for driving the laundry basket under the heavy load of a washing cycle. Also, three additional speeds are provided for spinning the laundry basket at increased speed increments so that as the water is removed by the spinning action, the spin speed may be increased.

The transmission 10 is conditioned for first speed by actuating the solenoids 47 and 52 which in turn will move the plungers 48 and 53 into the path of the ends 46 and 51 of springs so as to cause the disengagement of the helical clutch springs and respectively. As a result of the disengagement of the spring clutches 45 and 50 the first speed drive is completed through the small drive gear 25, the large driven gear 38 and the intermediate driven gear 40 by virtue of the normally engaging helical clutch spring 54, the idler shaft 13, the small driven gear 43, the large drive gear 33, the cylindrical drum 35 by virtue of the normally engaged overriding spring clutch 55 and out through the driven shaft 12.

A second speed obtained by actuating the solenoid 52 only so as to cause the plunger 53 to engage the spring end 51 of the spring clutch 50 and thereby release the spring clutch 50 from a normally engaged driving relation between the intermediate and the large drive gears 27 and 33 respectively. The second speed gear ratio is thereupon provided through the small drive gear 25 and the intermediate drive gear 27 by virtue of the normally actuated helical spring clutch 45, the intermediate driven gear 40, the idler shaft 13, the small driven gear 43, the large drive gear 33, and out through the driven shaft clutch 12 by virtue of the normally actuated helical spring clutch 55 interconnecting the large drive gear 33 and the clutch drum 35. It should be noted that the spring clutch 54 will release so as to allow an overriding relation between the large and intermediate driven gears 38 and 40.

A third speed is provided by actuating the solenoid 47 only so as to cause the plunger 48 to engage the spring end 46 of the normally engaged helical spring clutch 45 and thereby release the clutch spring 45. The third speed is thereupon provided through the small drive gear 25, the large driven gear 38 and the intermediate driven gear 40 by virtue of the normally engaged spring clutch 54, the intermediate drive gear 27 and the first clutch drum 30 by virtue of the normally engaged spring clutch 50, and out through the driven shaft 12. It should be noted that the spring clutch 55 will release so as to allow an overriding relation between the large drive gear 33 and the driven shaft 12.

The fourth speed is provided when neither of the solenoids 47 or 52 are actuated and both of the releasable helical spring clutches 45 and 50 are thereby allowed to exert their normal resilient connection between the small and intermediate drive gears 25 and 27 and the intermediate and large drive gears 27 and 33 respectively. The fourth speed is thereupon provided through the small drive gear 25 and the intermediate drive gear 27 by virtue of the normally engaged releasable spring clutch 45, the intermediate drive gear 27 and the clutch drum 30 by virtue of the normally releasable spring clutch 50, and out through the driven shaft 12. It should be noted that the spring clutch 54 will release so as to provide an override relation between the large and intermediate driven gears 38 and 40 respectively. Also, clutch springs 55 will release so as to provide an override relation between the large drive gear 33 and the driven shaft 12.

A tabulation is provided below which graphically indicates which of the friction devices are engaged or disengaged for each of the four speed ratios above described in reference to the transmissions illustrated in FIG. 1. It should be noted that the gear ratios indicated in the tabulation are the approximate ratios provided by a particular embodiment of the invention and in no way restrict the invention to a specific arrangement or con- 'struction.

Gear Clutches Clutches Ratio Engaged Dlsengaged 54 and 55 45 and 50 8.5 45 and 55 50 and 54 4. 7 50 and 54 45 and 55 1.8 45 and 50 54 and 55 1.0

It should be noted that the preferred embodiment of the invention, as above described, provides a four speed washing machine transmission which includes a low speed drive for driving the laundry basket during the Washing cycle, and three higher speeds for spinning the laundry to remove the water with increasing speed as the water is removed. Further, it should be noted that the four speeds may be selectively provided by individual, remote, electric actuation of only two solenoids. Also, it should be noted that the drive shaft is coaxial with the driven shaft and that all clutch drive connections are resilient.

Another embodiment of the invention (FIG. 2) illustrates a transmission, generally referred to by the numeral a, which is similar to the embodiment shown in FIG. 1 and it should be noted that like numbers refer to like elements of the respective embodiments illustrated in FIGS. 1 and 2. However, the transmission 10a (FIG. 2) illustrated does not utilize the overriding helical spring clutch 55, the pins 32 and 41 and the clutch drums 39 and 35. Instead a pin 59 is provided to secure the large drive gear 33 to the driven shaft 12. The large drive gear 33 is provided with a clutch drum 60 positioned within the clutch spring 51 Also, an overriding spring clutch 61 is mounted on a cylindrical clutch drum surface 63 formed on the intermediate driven gear 49 and on an adjacent cylindrical clutch drum surface 64 formed on the small driven gear 43.

The spring clutch 61 is a self-energizing overriding clutch spring which reacts with the drum surfaces 63 and 64 to provide a resilient connection between the intermediate and small driven gears 40 and 43. inasmuch as the spring clutch 61 is an overriding clutch spring, the small driven gear 43 will override the intermediate driven gear at) when the small driven gear 43 is driven by the large drive gear 33.

In operation, the transmission 10a (FIG. 2) is adapted to provide four speeds forward including a low speed for driving the laundry basket under the heavy load of a washing cycle. Also, three additional speeds are provided for spinning the laundry basket at increased speed increments so that as the water is removed by the spinning action, the spin speed may be increased.

The transmission 10a is conditioned for first or low speed by actuating the solenoids 47 and 52 which in turn will move the plungers 48 and 53 into the path of the ends 46 and 51 of the clutch springs 45 and 5t respectively so as to cause disengagement of the helical spring clutches 45 and 59. As a result of the disengagement of the spring clutches 45 and 59 the first speed drive is completed through the small drive gear 25, the large driven gear 38 and the intermediate driven gear 40 by virtue of the normally engaged helical spring clutch 54, the intermediate driven gear 40 and the small driven gear 43 by virtue of the normally engaged helical spring clutch 61, the large drive gear 33, and out through the driven shaft 12.

A second speed is obtained by actuating the solenoid 52 only so as to cause the plunger 53 to engage the spring end 51 of the spring clutch 50 to release the spring clutch 50 from a normally engaged driving relation between the intermediate and large drive gears 27 and 33 respectively. The second speed gear ratio is thereupon provided through the small drive gear and the intermediate drive gear 27 by virtue of the normally actuated helical spring clutch 45, the intermediate drive gear 40 and the small driven gear 43 by virtue of the normally actuated spring clutch 61, the large drive gear 33, and out through the driven shaft 12. It should be noted that the spring clutch 54 will release so as to allow an override between the intermediate and large driven gears 38 and 40.

A third speed is provided by actuating the solenoid 47 only so as to cause the plunger 48 to engage the spring end 46 of the normally engaged helical spring 45 to release the spring clutch 45. The third speed is thereby provided through the small drive gear 25, the large driven gear 38 and the intermediate driven gear 40 by virtue of the normally engaged overriding spring clutch 54, the intermediate driven gear 27 and the large drive gear 33 by virtue of the normally engaged releaseable clutch spring 50, and out through the driven shaft 12. it should be noted that the clutch spring 61 will release so as to allow an override relation between the small driven gear 43 and the intermediate driven gear 40.

The fourth speed gear ratio is provided when neither of the solenoids are actuated and both of the releasable springs 45 and 50 are thereby allowed to assert their normal resilient connection between the small and intermediate drive gears 25 and 27 and between the intermediate and large drive gears 27 and 33 respectively. The fourth speed is thereby provided through the small drive gear 25 and the intermediate drive gear 27 by virtue of the normally engaged releasable spring clutch 45, through the intermediate drive gear 27 and the large drive gear 33 by virtue of the normally engaged releasable spring clutch 5b and out through the driven shaft 12. It should be noted that the spring clutches 54 and 6 1 will release so as to provide an overriding relation between the intermediate and large driven gears 40 and 38 respectively, and between the small and intermediate driven gears 43 and 4t respectively.

A tabulation is provided below which graphically indicates which of the friction devices are engaged or disengaged for each of the four speed ratios above described in reference to the transmission illustrated in FIG. 2. It should be noted thalt'the gear ratios indicated in the tabulation are the appnoximate relations provided by a particular embodiment of the invention and in no way restrict the invention to a specific arrangement or construction.

Gear Clutches Clutches Ratio Engaged Disengaged 54 and 61 45 and 50 8.0 45 and 61 50 and 54 5. 5 50 and 54 45 and 61 l. 5 45 and 50 54 and 61 1.0

It should be noted that the embodiment of the invention as above described and as illustrated in FIG. 2 similarly provides a four speed washing machine transmission which includes a low speed drive for driving the laundry basket during the Washing cycle and three higher speeds for spinning the laundry to remove the water with increasing speed as the water is removed. Further, it should be noted that the four speeds are selectively provided by remote electric actuation of only two solenoids. Also, it should be noted that the drive shaft is coaxial with the driven shaft and that the clutch drive connections are resilient.

I wish it to be understood that the invention not to be limited to the specific constructions and arrangements shown and described, except only insofar as the claims may be so limited, as it will be understood to those skilled in the art that changes may be made Without departing from the principles of the invention.

What is claimed is:

1. In a variable speed transmission comprising a casing, a drive shaft notatably mounted in said casing, a driven shaft element rotatably mounted in said casing and coaxially within said drive shaft, an idler shaft element rotatably mounted in said casing parallel to said drive shaft, first, second, and third drive gear elements coaxially mounted on said driven shaft, said first drive gear element being rotatable with said drive shaft, first, second, and third driven gear elements coaxially mounted on said idler shaft in meshing engagement with said first, second, and third drive gear elements respectively, first and second self-engaging ioverrunning clutches for pnoviding driving interconnections between four elements of the transmission and adapted to disengage in response to ovcrrunning tendency between the elements normally interconnected thereby, first and second self-engaging releasable clutches for providing driving interconnections between four remaining elements of the transmission and adapted to be selectively actuated for providing four speed-s forward, and means for selectively actuating said releasable clutches.

2. In a variable speed transmission comprising a casing, a drive shaft element rotatably mounted in said casing, a driven shaft element rotatably mounted in said casing and ooaxially within said drive shaft, an idler shaft element rotatably mounted in said casing parallel to said drive shaft, first, second and third drive gear elements ooaxially mounted on said driven shaft, said first drive gear element being rotatable with said drive shaft, first, second, and third driven gear elements coaxially mounted on said idler shaft in meshing engagement with said first, second, and third drive gear elements respectively, first and second self-engaging ovcrrunning helical spring clutches for providing driving interconnections between four elements of the transmission and adapted to disengage in response to ovcrrunning tendency between any two of the elements normally interconnected thereby, first and second self-engaging releasable helical spring clutches for providingdriving interconnections between the four remaining elements of the transmission and adapted to be selec tively actuated for providing four speeds forward, and means for selectively actuating said releasable clutches.

3. In a variable speed transmission comprising a casing, a drive shaft rotatably mounted in said casing, a driven shaft rotatably mounted in said casing and coaxially within said drive shaft, an idler shaft rotatably mounted in said casing parallel to said drive shaft, a first drive gear formed on said drive shaft, second and third drive gears rotatably mounted on said driven shaft, a first driven gear rotatably mounted on said idler shaft, second and third driven gears secured to said idler shaft, said driven gears being respectively in mesh with said drive gears, a first releasable self-engaging clutch mounted on said first and second drive gears for releasably interconnecting said first and second drive gears, a second releasable.self engaging clutch releasably interconnecting said second drive gear with said driven shaft, a first ovcrrunning self-engaging clutch interconnecting said drive gear and said driven shaft, or second ovcrrunning self-engaging clutch for interconnecting said first and second driven gears, and means for independently-releasing said first and second self-engaging clutches to provide four forward speeds between said drive and said driven shafts.

4. In a variable speed transmission comprising a casing, a drive shaft rotatably mounted in said casing, a driven shaft rotatably mounted in said casing and coaxially within said drive shaft, an idler shaft rotatably mounted in said casing parallel to said drive shaft, a first drive gear formed on said drive'shaft, second and third drivegears rotatably mounted on said driven shaf-h'a first driven gear rotatably mounted on said idler shaft, second and a third driven gears secured to said idler shaft, said driven'gears being respectively in mesh with said drive gears, a first normally engaged releasable helical spring clutch mounted on said first and second drive gears for releasably interconnecting said gears, asecond-normally engaged releasable helical spring clutch mounted on said second drive gear and said driven shaft for releasably connecting said gear with said shaft, a first ovcrrunning normally engaged helical spring clutch mounted on said third drive gear and said driven shaft for interconnecting said gear and said shaft, a second ovcrrunning normally engaged helical spring clutch mounted on said first driven gear and said second driven gear for itnerconnecting said gears, and means for independently releasing said first and second normally engaged spring clutches to provide four forward speeds between said drive and said driven'shafts.

5 In a variable speed transmission comprising a casing, a drive shaft rotatably mounted in said casing, a driven shaft rotatably mounted in said casing and coaxially with in said drive shaft, an idler shaft rotatably mounted in said casing parallel to said drive shaft, a first drive gear formed on said drive shaft, second and third drive gears rotatably mounted on said driven shaft, a first driven gear rotatably mounted on said idler shaft, second and third driven gears secured to said idler shaft, said driven gears being respectively in mesh with said drive gears, clutch drum surfaces provided by adjacent sides of said first and second drive gears, adjacent clutch drum surfaces provided by the second drive gear and said drive shaft, adjacent clutch drum surfaces provided by said third drive gear and said driven shaft, clutch drum surfaces provided by adjacent sides of said first and second driven gears, a first self-engaging releasable spring mounted on said first and second drive gear clutch drums forreleasably interconnecting said gears, a second self-engaging releasable spring mounted on said second drive gear and said driven shaft drum surfaces for releasably interconnecting said gear with said shaft, a first ovcrrunning self-engaging spring mounted on said third drive gear clutch drum surface and said adjacent driven shaft clutch drum surface for interconnecting said gear and said shaft, a second ovcrrunning self-engaging spring mounted on said first driven gear clutch drum surface and said second driven gear clutch drum surface for interconnecting said gears and, means for independently releasing said first and second releasable self-engaging springs to provide four forward speeds between said drive and said driven shafts.

6. In a variable speed transmission comprising a casing, a drive shaft rotatably mounted in said casing, a driven shaft rotatably mounted in said casing and coaxially within said drive shaft, an idler shaft rotatably mounted in said casing parallel to said drive shaft, a first drive gear formed on said drive shaft, second and third drive gears rotatably mounted on said driven shaft, a first driven gear rotatably mounted on said idler shaft, second and third driven gears secured to said idler shaft, said driven gears being respectively in mesh with said drive gears, clutch drum surfaces provided by adjacent sides of said first and second drive gears, adjacent clutch drum surfaces providedby the second drive gear and said drive shaft, ad jacent clutch drum surfaces provided by said third drive gear and said driven shaft, clutch drum surfaces provided by adjacent sides of said first and second driven gears, a first'normally engaged releasable helical spring mounted on said first and second drive gear clutch drums for releasably interconnecting said gears, a second normally engaged releasable helical spring mounted on said second drive gear and said driven shaft for releasably connecting said gear with said shaft, a first ovcrrunning normally engaged helical spring mounted on said third drive gear cdlutch drum and said adjacent driven shaft clutch drumfor interconnecting said gear and said shaft, a second ovcrrunning normally engaged helical spring mounted on said first driven gear clutch drum and said second driven gear clutch drum for interconnecting said gears, and means for independently releasing said first and second normally engaged springs to provide four forward speeds between said drive and said driven shafts.

7. In a variable speed transmission comprising a casing, a drive shaft rotatably mounted in said casing, a driven shaft rotatably mounted in said casing and coaxilly Within said drive shaft, an idler shaft rotatably mounted in said casing parallel to said drive shaft, a first drive gear formed on said drive shaft, a second drive gear rotatably mounted on said driven shaft, a third drive gear secured to said driven shaft, first and second driven gears rotatably mounted on said idler shaft, a third driven gear secured to said idler shaft, said first, second, and third driven gears being respectively in mesh with said first second and third drive gears, a first self-engaging releasable clutch mounted on said first and second drive gears for releasably interconnecting said first and second drive gears, a second self-engaged releasable clutch mounted on said second and third drive gears for releasably interconnecting said second and third drive gears, a first overrunning self-engaged clutch mounted on said first and second driven gears for interconnecting said first and second driven gears, a second overrunning self-engaging clutch mounted on said second and third driven gears for interconnecting said second and third driven gears, and means for independently releasing said first and second self-engaging releasable clutches to provide four forward speeds between said drive and said driven shafts.

8. In a variable speed transmission comprising a casing, a drive shaft rotatably mounted in said casing, a driven shaft rotatably mounted in said casing and coaxially within said drive shaft, an idler shaft rotatably mounted in said casing parallel to said drive shaft, a first drive gear formed on said drive shaft, a second drive gear rotatably mounted on said driven shaft, a third drive gear secured to said driven shaft, first and second driven gears rotatably mounted on said idler shaft, a third driven gear secured to said idler shaft, said first, second, and third driven gears being respectively in mesh with said first, second, and third drive gears, a first normally engaged releasable helical spring clutch mounted on said first and second drive gears for releasably interconnecting said first and second drive gears, a second normally engaged releasable helical spring clutch mounted on said second and third drive gears for releasably interconnecting said second and third drive gears, a first overrunning normally engaged helical spring clutch mounted on said first and second driven gears for interconnecting said first and second driven gears, a second overrunning normally engaged [helical spring clutch mounted on said second and third driven gears for interconnecting said second and third driven gears, and means for independently releasing said first and second normally engaged spring clutches to provide four forward speeds between said drive and said driven shafts.

9. In a variable speed transmission comprising a casing, a drive shaft rotatably mounted in said casing, a driven shaft rotatably mounted in said casing and coaxially within said drive shaft, an idler shaft rotatably mounted in said casing parallel to said drive shaft, a first drive gear formed on said driven shaft, a second drive gear rotatably mounted on said driven shaft, a third drive gear secured to said driven shaft, first and second driven gears rotatably mounted on said idler shaft, a third driven gear secured to said idler shaft, said first, second, and third driven gears being respectively in mesh with said first, second, and third drive gears, clutch drum surfaces provided by adjacent sides of said first and second drive gears and said second and third drive gears, clutch drum surfaces provided by adjacent sides of said first and second driven gears and said second and third gears, a first self-engaging releasable spring mounted on said first and second drive gear clutch dmms for releasably interconnecting said first and second drive gears, a second selfengaging releasable spring mounted on said second and third drive gear clutch drums for releasably interconnecting said second and third drive gears, a first overrunning self-engaging spring mounted on said first and second driven gear clutch drums for interconnecting said first and second driven gears, a second overrunning self-engaging spring mounted on said second and third driven gear clutch drums for interconnecting said second and third driven gears, and a means for independently releasing said first and second self-engaging releasable springs to provide four forward speeds between said drive and said driven shafts.

'10. In a variable speed transmission comprising a casing, a drive shaft rotatably mounted in said casing, a driven shaft rotatably mounted in said casing and coaxially within said drive shaft, an idler shaft rotatably mounted in said casing parallel to said drive shaft, a first drive gear formed on said drive shaft, a second drive gear rotatably mounted on said driven shaft, a third drive gear secured to said driven shaft, first and second driven gears rotatably mounted on said idler shaft, a third driven gear secured to said idler shaft, said first, second, and third driven gears being respectively in mesh with said first, second, and third drive gears, clutch drum surfaces provided by adjacent sides of said first and second drive gears and said second and third drive gears, clutch drum surfaces provided by adjacent sides of said first and second driven gears and said second and third driven gears, a first normally engaged releasable helical spring mounted on said first and second drive gear clutch drums for releasably interconnecting said first and second drive gears, a second normally engaged releasable helical spring mounted on said second and third drive gear clutch drums for releasably interconnecting said second and third drive gears, a first overrunning normally engaged helical spring mounted on said first and second driven gear clutch drums for interconnecting said first and second driven gears, a second overrunning normally engaged helical spring mounted on said second and third driven gear clutch drums for connecting said second and third driven gears, and means for independent- 'ly releasing said first and second normally engaged springs to provide four forward speeds between said drive and said driven shafts.

References Cited in the file of this patent UNITED STATES PATENTS 2,660,899 McCammon Dec. 1, 1953 2,819,624 Brown et al Jan. -14, (1958 2,881,640 Chambers Apr. 14, 1959 

1. IN A VARIABLE SPEED TRANSMISSION COMPRISING A CASING, A DRIVE SHAFT ROTATABLY MOUNTED IN SAID CASING, A DRIVEN SHAFT ELEMENT ROTATABLY MOUNTED IN SAID CASING AND COAXIALLY WITHIN SAID DRIVE SHAFT, AN IDLER SHAFT ELEMENT ROTATABLY MOUNTED IN SAID CASING PARALLEL TO SAID DRIVE SHAFT, FIRST SECOND, AND THIRD DRIVE GEAR ELEMENTS COAXIALLY MOUNTED ON SAID DRIVEN SHAFT, SAID FIRST DRIVE GEAR ELEMENT BEING ROTATABLE WITH SAID DRIVE SHAFT, FIRST, SECOND, AND THIRD DRIVEN GEAR ELEMENTS COAXIALLY MOUNTED ON SAID IDLER SHAFT IN MESHING ENGAGEMENT WITH SAID FIRST, SECOND, AND THIRD DRIVE GEAR ELEMENTS RESPECTIVELY, FIRST AND SECOND SELF-ENGAGING OVERRUNNING CLUTCHES FOR PROVIDING DRIVING INTERCONNECTIONS BETWEEN FOUR ELEMENTS OF THE TRANSMISSION AND ADAPTED TO DISENGAGE IN RESPONSE TO OVERRUNNING TENDENCY BETWEEN THE ELEMENTS NORMALLY INTERCONNECTED THEREBY, FIRST AND SECOND SELF-ENGAGING RELEASABLE CLUTCHES FOR PROVIDING DRIVING INTERCONNECTIONS 